| US 7,456,458 B2 | ||
| Dynamic random access memory structure | ||
| Ting Sing Wang, Hsinchu (Taiwan) | ||
| Assigned to Promos Technologies Inc., (Taiwan) | ||
| Filed on Apr. 13, 2006, as Appl. No. 11/402,871. | ||
| Claims priority of application No. 95100997 A (TW), filed on Jan. 11, 2006. | ||
| Prior Publication US 2007/0158719 A1, Jul. 12, 2007 | ||
| Int. Cl. H01L 27/108 (2006.01) | ||
| U.S. Cl. 257—296 [257/E21.637; 257/329; 438/268] | 14 Claims |
| 1. A dynamic random access memory structure, comprising:
a substrate having a plurality of pillars, each pillar including:
an upper conductive region positioned on a top portion of the pillar;
a body capable of storing carriers positioned below the upper conductive region in the pillar; and
a bottom conductive region positioned below the body in the pillar;
a gate oxide layer positioned on a sidewall of the pillar;
a gate structure positioned on a surface of the gate oxide layer; and
an oxide layer including a base positioned on the substrate and a protrusion in a bottom portion of the pillar, the bottom
conductive region being sandwiched between the protrusion and the body,
wherein the pillar is cylindrical.
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